I think the hollow earth stuff is nonsense, too.
Lots of very bright folks have believed in crazy notions.
That still does not negate his research in the oil field.
On the other hand, we all have accepted a very long list of ‘facts’ as facts . . . because we were told they were facts by convincing folks and/or convincing authorities.
And, there is another plausibility . . . he angered powerful folks sufficiently that they targeted him with very effective . . . influences . . . sending him off on such a reputation scuttling exercise.
Or perhaps you believe the government has 0.000000000% capacity to do such things or to trash reputations.
John Lear might disagree with that kind of belief.
And, he has some funny notions, too.
Lot’s of nuts and fruits swerve into the truth now and again.......